41 research outputs found

    Search for ultra high energy gamma-rays from various sources

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    The hypothesis that there exists an excess of showers from the Galactic plane on the level 1 to 2% at energies just above 10 to the 16th power eV is explored. The excess shower from the Galactic plane seems to be very similar in properties to excess showers from the point sources/flat spectrum, deficit of low energy muons. Those facts suggest that the excess from the Galactic plane are probably due to summing up of the contribution from individual point sources. That in turn suggest that those sources are rather numerous

    New results on source and diffusion spectral features of Galactic cosmic rays: I- B/C ratio

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    In a previous study (Maurin et al., 2001), we explored the set of parameters describing diffusive propagation of cosmic rays (galactic convection, reacceleration, halo thickness, spectral index and normalization of the diffusion coefficient), and we identified those giving a good fit to the measured B/C ratio. This study is now extended to take into account a sixth free parameter, namely the spectral index of sources. We use an updated version of our code where the reacceleration term comes from standard minimal reacceleration models. The goal of this paper is to present a general view of the evolution of the goodness of fit to B/C data with the propagation parameters. In particular, we find that, unlike the well accepted picture, and in accordance with our previous study, a Kolmogorov-like power spectrum for diffusion is strongly disfavored. Rather, the χ2\chi^2 analysis points towards δ0.7\delta\gtrsim 0.7 along with source spectra index 2.0\lesssim 2.0. Two distinct energy dependences are used for the source spectra: the usual power-law in rigidity and a law modified at low energy, the second choice being only slightly preferred. We also show that the results are not much affected by a different choice for the diffusion scheme. Finally, we compare our findings to recent works, using other propagation models. This study will be further refined in a companion paper, focusing on the fluxes of cosmic ray nuclei.Comment: 32 pages, 13 figures, accepted in A&

    Constraining Galactic cosmic-ray parameters with Z<=2 nuclei

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    The secondary-to-primary B/C ratio is widely used to study Galactic cosmic-ray propagation processes. The 2H/4He and 3He/4He ratios probe a different Z/A regime, therefore testing the `universality' of propagation. We revisit the constraints on diffusion-model parameters set by the quartet (1H, 2H, 3He, 4He), using the most recent data as well as updated formulae for the inelastic and production cross-sections. The analysis relies on the USINE propagation package and a Markov Chain Monte Carlo technique to estimate the probability density functions of the parameters. Simulated data are also used to validate analysis strategies. The fragmentation of CNO cosmic rays (resp. NeMgSiFe) on the ISM during their propagation contributes to 20% (resp. 20%) of the 2H and 15% (resp. 10%) of the 3He flux at high energy. The C to Fe elements are also responsible for up to 10% of the 4He flux measured at 1 GeV/n. The analysis of 3He/4He (and to a less extent 2H/4He) data shows that the transport parameters are consistent with those from the B/C analysis: the diffusion model with delta~0.7 (diffusion slope), Vc~20 km/s (galactic wind), Va~40 km/s (reacceleration) is favoured, but the combination delta~0.2, Vc~0, and Va~80 km/s is a close second. The confidence intervals on the parameters show that the constraints set by the quartet data are competitive with those brought by the B/C data. These constraints are tighter when adding the 3He (or 2H) flux measurements, and the tightest when further adding the He flux. For the latter, the analysis of simulated and real data show an increased sensitivity to biases. Using secondary-to-primary ratio along with a loose prior on the source parameters is recommended to get the most robust constraints on the transport parameters.Comment: 17 pages, 7 tables, 20 figures (submitted to A&A

    The ERA-EDTA Registry Annual Report 2017 : a summary

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    Background. This article presents a summary of the 2017 Annual Report of the European Renal Association-European Dialysis and Transplant Association (ERA-EDTA) Registry and describes the epidemiology of renal replacement therapy (RRT) for end-stage renal disease (ESRD) in 37 countries. Methods. The ERA-EDTA Registry received individual patient data on patients undergoing RRT for ESRD in 2017 from 32 national or regional renal registries and aggregated data from 21 registries. The incidence and prevalence of RRT, kidney transplantation activity and survival probabilities of these patients were calculated. Results. In 2017, the ERA-EDTA Registry covered a general population of 694 million people. The incidence of RRT for ESRD was 127 per million population (pmp), ranging from 37 pmp in Ukraine to 252 pmp in Greece. A total of 62% of patients were men, 52% were >= 65 years of age and 23% had diabetes mellitus as the primary renal disease. The treatment modality at the onset of RRT was haemodialysis for 85% of patients. On 31 December 2017, the prevalence of RRT was 854 pmp, ranging from 210 pmp in Ukraine to 1965 pmp in Portugal. The transplant rate in 2017 was 33 pmp, ranging from 3 pmp in Ukraine to 103 pmp in the Spanish region of Catalonia. For patients commencing RRT during 2008-12, the unadjusted 5-year patient survival probability for all RRT modalities combined was 50.8%.Peer reviewe

    The Polish United Workers’ Party in the district of Mrągowo in 1948–1989

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    The Poviat Committee of the Polish Workers ‘Party in Mrągowo was established on July 13, 1945. In December 1948, after joining the local organization of the Polish Socialist Party, it transformed into a Poviat Committee of the Polish United Workers’ Party in Mragowo. This structure functioned until mid-1975, when it was dissolved. After the liquidation of the district committee, all party organizations from the area of the abolished Poviat were subordinated to the Provincial Committee of the PZPR in Olsztyn. The total number of party members in the Poviat was systematically increasing from less than 1500 at the time of the establishment of the PZPR, to over 2600 at the time of the Poviat’s liquidation. The last reliable data from 1988 regarding the number of PZPR members was 1800. The largest party organization had the PZPR Mu�nicipal Committee in Mrągowo, gathering 40–50% of all party members in the aforementioned area. The PZPR organization in Mrągowo experienced two major organizational crises: in 1956 and in the years 1980–1982. The second of them brought losses, which proved to be impossible to mitigate. Individual branches lost up to 20% of their members, there was chaos in the organization and there were no people willing to perform party functions. The disintegration of the organization was halted in 1984–1986. In the last years of the PZPR (1987–1989) only its superior structures, i.e. committees, were active. The basic branches ceased operations well before the formal dissolution of the party
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